Pinion with lubrication device

Abstract

The invention relates to a pinion (10a) extending around an axis of a shaft (11), comprising teeth (13) carried by a crown (14) connected to said shaft by a conical web (12) which extends from an end of the shaft and widens towards the crown away from said end, the pinion comprising a lubrication device comprising a lubricant inlet on an internal wall of the conical web and channels (15a), hollowed out in the crown (14) which open into hollows (13a) between the teeth (13) of the pinion. The invention further relates to a lubricated meshing device and a gearbox comprising said pinion. Figure 1

Description

Title of the invention: Pinion with lubrication device Technical field

[0001] The technical field of the invention is that of the lubrication of gear meshes, in particular gears of aircraft turbomachines and more particularly those used for accessory drive systems or "accessory gearboxes" (ADT) and transfer boxes or "transfer gearboxes" (TGB). Prior art

[0002] In turbomachines, part of the power generated by the turbine is used to drive various accessories necessary for the operation of the turbomachine or an aircraft equipped with it, such as an electric generator, lubrication pump or fuel pump.

[0003] For this purpose, a traditional turbomachine 201 as shown in [fig.5] generally comprises an input gear box 220 (IGB: Inlet Gear Box), a radial drive shaft 215 (RDS: Radial Drive Shaft), a transfer gear box 221 (TGB: Transfer Gear Box) and an accessory gear box 206 (AGB: Accessory Gear Box) supporting the various accessories.

[0004] When the drive shaft 211 of the turbomachine is driven in rotation, it mechanically drives the various accessories via the IGB 220, the RDS 215, the TGB 221 and then the AGB 206. LTGB and the TGB provide an angle transmission which makes it possible to switch from a longitudinal rotation system to a transverse rotation system on the same turbomachine by gear mechanisms.

[0005] The AGB transmits the rotational movement of the various accessories by a combination of gears called a gear train. The assembly formed by the AGB and the accessories can be positioned in the casing of the turbomachine, close to the fan in an area called the "fan zone" or in a "core" zone, that is to say in a central zone of the turbomachine, around the high-pressure compressor.

[0006] In TGB gearboxes, it is necessary for operational reasons (seizing, heating, etc.) to lubricate the meshing. The rotation speed of the pinions is a factor in poor lubrication because it prevents the jet of lubricant, sent by a nozzle, from reaching the meshing point. The jet of lubricant is "cut" by the teeth before reaching the tooth flanks.

[0007] Today, to lubricate a gear mesh, in certain cases, a jet from a nozzle is used which targets the mesh from the outside, the nozzle being able to be integrated into a deflector device. In this case, it is necessary to reduce the length of the jet because if it is too far from the teeth, it will be deflected or "broken" by the wind due to the rotation of the pinions. This is why, to ensure sufficient lubrication, it is then necessary to use a significant quantity of lubricant. In the case where the pinion extends around an axis and includes a shaft and teeth carried by a web which extends around the shaft, it is also possible to use a lubrication device comprising jets located on the inside of the pinion and including outlet holes which open between the teeth of the pinion. Such an arrangement is however more complicated and requires the production of an additional mechanical part which makes the device heavier.

[0008] Furthermore, in the context of hybridization studies, ADT accessories are required to have higher rotation speeds compared to accessories of traditional turbo-machines, which increases the phenomenon of jet deviation or breakage and makes jet lubrication more difficult. Statement of the invention

[0009] The invention provides a solution to the problems mentioned above, by making it possible to improve the supply of lubricant to the meshing while limiting the quantity of lubricant required by means of a pinion provided with means for lubricating the teeth.

[0010] More specifically, the invention provides a pinion extending around an axis of a shaft, comprising teeth carried by a crown connected to said shaft by a conical web, which extends from an end of the shaft and widens towards the crown moving away from said end, the pinion comprising a lubrication device comprising a lubricant inlet on an internal wall of the conical web and channels, hollowed out in the crown which open into hollows between the teeth of the pinion.

[0011] This configuration, in which lubrication is carried out from the inside of the pinion, minimizes the parts required for lubrication and reduces its weight. It brings the lubricant, which is generally oil, as close as possible to the hollows of the teeth without the nozzle being too close to the latter and being disturbed by the wind created by their rotation.

[0012] The characteristics set out in the following paragraphs correspond to embodiments which can be implemented independently of one another or in combination with one another.

[0013] The channels can open at the level of the hollows between the teeth on the side of the axis of rotation of the pinion, which brings the lubricant directly into these hollows to form a film there.

[0014] The lubricant is thus injected directly at the base of the teeth and, with centrifugal force, the lubricant will migrate towards the top of the tooth and outwards.

[0015] According to a first embodiment, the channels are grooves hollowed out in a lateral internal wall of the crown on the rotation axis side and opening into the hollows of the teeth at the end of the teeth on the rotation axis side. In this case the lubricant flows into the hollows from the inner face of the crown carrying the teeth.

[0016] According to a second embodiment, the channels are tubular channels opening on a first side through lubricant inlet holes in the web or in an internal wall of the crown extending the web and on a second side through lubricant outlet holes at the bottom of the hollows between the teeth to bring the lubricant into these hollows. This configuration makes it possible to bring the lubricant under the teeth of the complementary pinion.

[0017] The inner wall of the crown may comprise a curved inner rim at a junction between the inner wall of the conical web and the crown so as to produce an annular hollow forming a reserve for the lubricant pressed against said inner wall by the centrifugal force caused by the rotation of the pinion. This reserve may in particular be used to start lubrication at low rotation speed of the pinion.

[0018] The number of channels, tubular channels or grooves, is advantageously equal to the number of hollows between the teeth.

[0019] The pinion may be a bevel or straight pinion and have helical or straight teeth, the lubricant being distributed in the hollows between the teeth under the action of the centrifugal force due to the rotation of the pinion.

[0020] The device may comprise at least one nozzle whose outlet is directed towards the web of the pinion. The nozzle then sprays the web, which distributes the lubricant over the surface of the web.

[0021] Advantageously, the nozzle deposits the lubricant at the foot of the shaft-side web, which spreads the lubricant over the web in the direction of the channels, while the rotation of the pinion will drive the lubricant towards the peripheral part of the web and the channels by centrifugal force and propel it between the teeth. This makes it possible to supply lubricant directly into the mesh without any additional mechanical part.

[0022] According to one embodiment, the pinion is a helical-toothed pinion. The pinion could also be a straight-toothed pinion.

[0023] The pinion can be a straight or bevel pinion, the latter type of pinion being used in particular for the angle transmissions of transfer boxes.

[0024] The invention also relates to a device for meshing two pinions comprising at least one pinion with at least one of the preceding characteristics.

[0025] The meshing device advantageously comprises a first pinion according to the invention, at least one nozzle whose outlet is directed towards the web of said first pinion and a second pinion provided or not with the lubrication device of the invention, the first pinion being meshed with the second pinion.

[0026] The nozzle advantageously deposits the lubricant on the shaft-side web, so that the centrifugal force caused by the rotation of the pinion spreads the lubricant on the web in the direction of the channels. The nozzle can in particular deposit the lubricant at the foot of the web.

[0027] The invention applies to a gearbox of a turbomachine comprising at least one meshing device according to the invention. Brief description of the drawings

[0028] Other characteristics, details and advantages of the invention will appear on reading the detailed description below of non-limiting exemplary embodiments, and on analyzing the appended drawings, in which:

[0029] [fig. 1] shows a perspective view of a gear provided with a lubrication device according to a first embodiment;

[0030] [fig.2] shows a perspective sectional detail of the gear device of [fig.l];

[0031] [fig.3] shows a perspective view of a gear provided with a lubrication device according to a second embodiment;

[0032] [fig.4] shows a perspective sectional detail of the gear device of [fig.3];

[0033] [fig.5] shows a schematic representation in longitudinal section of an example of a turbomachine of the prior art;

[0034] [fig.6] shows a schematic cross-sectional representation of a gearing device according to one embodiment of the invention. Description of the embodiments

[0035] The following drawings and description contain elements which may not only serve to better understand the present invention, but also contribute to its definition, where appropriate.

[0036] [Fig. 1] shows a gear provided with a first pinion 10a and a second pinion 20. The pinions shown are pinions with bevel teeth and helical teeth but the invention can be applied to any type of pinion. The pinion 10a has a toothing 13 carried by an annular crown 14 or a rim which is connected to a shaft 11 by means of a conical web 12.

[0037] The conical web which can also be a straight web extends from an end of the shaft 11 and widens towards the crown moving away from said end.

[0038] According to the invention, the pinion comprises a device for lubricating the teeth of the pinion comprising a lubricant inlet on an internal wall of the conical web and channels, here in the form of grooves 15a hollowed out in a wall 141a on the inside of the crown 14. The wall 141a is circular on the inside of the crown around the axis A of rotation of the pinion.

[0039] The grooves 15a more precisely represented in [fig.2] open into hollows 13a between the teeth 13 of the pinion, at the end of these hollows on the inside of the pinion. The lubricant, which is for example oil, flows onto the wall of the disc under the action of the centrifugal force created by the rotation of the pinion and is guided into the grooves between the teeth.

[0040] The grooves which open between the teeth are radial or mainly radial grooves.

[0041] The internal wall 141a of the crown may further comprise a curved rim 14a facing towards the inside of the pinion at a junction between the internal wall of the conical web and the crown so as to produce an annular hollow which forms a reserve for the lubricant pressed against said internal wall by the centrifugal force caused by the rotation of the pinion and which retains at least temporarily a portion of the lubricant to guide it towards the grooves between the hollows of the teeth.

[0042] In the example of Figures 3 and 4, representing a pinion 10b of an alternative embodiment, the channels are tubular channels 15b made in the crown 14. These tubular channels 15b open on a first side into the web or the internal wall 141b of the crown by lubricant inlet holes 152. These holes are here made near the flared end of the web at the junction between the web and the crown carrying the teeth. The tubular channels are provided on a second side with lubricant outlet holes 151 which open at the bottom of the hollows 13a between the teeth 13 in the inner part of the teeth to bring the lubricant into these hollows.

[0043] The inner part of the teeth is understood to mean the part of the teeth closest to the axis of rotation of the pinion.

[0044] The tubular channels are oriented radially or mainly radially relative to the pinion axis.

[0045] The number of outlet holes 151 is here equal to the number of hollows between the teeth to homogenize the distribution of the lubricant at the level of each hollow. It is the same in the example of figures 1 and 2 for the grooves 15a. It should be noted that the number of holes is not necessarily equal to the number of hollows, the holes being able to be distributed differently but preferably equally distributed to limit the unbalance of the pinion.

[0046] In this embodiment, the inner wall 141b of the crown also comprises a curved rim 14b to form a reservoir area for the lubricant.

[0047] According to the examples shown, the pinion is a bevel pinion particularly suitable for producing an angle transmission with the pinion 20 but the invention can also be applied to a straight pinion whose teeth are parallel or perpendicular to the axis of rotation of the pinion.

[0048] Furthermore, the pinion shown is a pinion with helical teeth but the invention can also be applied to pinions with straight teeth.

[0049] To supply the lubricant, a nozzle 30 is arranged in the pinion, its outlet projecting a jet of lubricant being directed towards the web of the pinion. The nozzle is preferably arranged at a sufficient distance from the teeth so that the jet is not broken by the edges of the teeth or by the wind caused by the rotation of the teeth. The nozzle can in particular be arranged at the foot of the web near the junction between the web and the shaft. Thus, the nozzle 30 deposits or projects the lubricant on the side of the foot of the web 12, so that the centrifugal force caused by the rotation of the pinion spreads the lubricant on the web in the direction of the channels 15a, 15b in a homogeneous manner.

[0050] The second pinion 20 of the meshing may or may not be provided with a lubrication device.

[0051] The power of the jet and its flow rate will be adapted according to the width of the grooves or the diameter of the tubular channels and the rotation speed of the pinions to provide correct lubrication at high rotation speed of the pinions.

[0052] The invention thus makes it possible to produce, without additional complex parts and without additional mass, a gearing device lubricated from the inside. This device does not interfere with the positioning of a casing or a protective cover around the crown and the teeth to avoid excessive oil projection under the effect of the centrifugal force due to the rotation of the pinions.

[0053] [fig.5] schematically represents a longitudinal section of a dual-flow aeronautical turbomachine 201 of the prior art in which at least one meshing device provided with at least one pinion 10a, 10b according to the invention can be implemented.

[0054] The turbomachine 201 with longitudinal axis XX comprises a fan casing 202, a low-pressure body 203, a high-pressure body 204, a combustion chamber and an accessory drive housing 206.

[0055] The low-pressure body 203 comprises a low-pressure shaft 207 centered on the longitudinal axis XX, a fan 208 mounted on the front end of the low-pressure shaft 207, a low-pressure compressor 209 fixed to the fan 208 downstream thereof, and a low-pressure turbine 210 mounted on the rear end of the low-pressure shaft 207.

[0056] The high-pressure body 204 comprises a high-pressure shaft 211 arranged concentrically around the low-pressure shaft 207, a first input gear 212 mounted at the front end of the high-pressure shaft 211, a high-pressure compressor 213 mounted on the high-pressure shaft 211 downstream of the first input gear 212 and a high-pressure turbine 214 mounted on the rear end of the high-pressure shaft 211.

[0057] It is noted that the different compressors 209, 213 and turbines 210, 214 of the low pressure 203 and high pressure 204 bodies of the turbomachine 201 shown in [fig.5] have been shown with a single stage of blades in order to facilitate their com- grip.

[0058] The AGB accessory drive box 206, fixed under the fan casing 202, is driven in rotation by the high-pressure shaft 211 via a radial drive shaft 215 carrying a first output pinion 216 at its upper end and a second input pinion 217 at its lower end, then via an input shaft 219 connected to the gear train of the AGB 206 and carrying a second output pinion 218. It should be noted that in other embodiments not shown, the AGB is positioned in the nacelle or in the so-called “core” zone of the turbomachine.

[0059] The term "pinions" means all types of toothed mechanical parts intended to cooperate with one or more toothed parts in order to transmit a rotational movement and within the framework of the present invention, at least some of said pinions can be produced according to the embodiments of figures 1 or 3.

[0060] The first input pinion 212 is meshed with the first output pinion 216 forming an angle transmission, the first input pinion 212 and the first output pinion 216 being housed in an input gear box IGB 220. Thanks to the cooperation of the first input pinion 212 with the first output pinion 216, a rotation of the high-pressure shaft 211 around the axis XX causes a rotation of the radial drive shaft 215 around its axis of rotation YY.

[0061] Furthermore, the second input pinion 217 is meshed with a second output pinion 218 of the accessory drive box 206, forming an angle transmission, the second input pinion 217 and the second output pinion 18 being housed in a transfer gear box TGB 221. Thanks to the cooperation of the second input pinion 217 with the second output pinion 218, a rotation of the radial drive shaft 15 about the axis YY causes a rotation of the input shaft 219 about its axis of rotation ZZ. The input shaft 219 thus transmits its power to a gear train (not shown) of the accessory drive box 206 which rotates the various accessories supported by said accessory drive box 206.Accessories include, for example, a fuel pump, an electric generator, a lubrication pump, a hydraulic pump, a starter, a constant speed transmission (CSD) or a tachometer.

[0062] In order to limit oil heating at the gears, a meshing device provided with one or two lubricated pinions according to the invention is for example positioned at the IGB and / or the TGB which will be described with reference to [fig.6]. It is noted that the meshing device according to the invention can be used for all types of gears of the turbomachine other than those described, i.e. two-pinion gears (bevel or straight / cylindrical) or multi-pinion gears (example: trio-bevel).

[0063] As shown in [fig.6], the gears of the IGB 220 and the TGB 221 are generally shrouded by a deflector which makes it possible to direct the air flow generated by the ventilation of the meshing in order, on the one hand, to protect the surrounding gravitational oil flows, and on the other hand, to eliminate the lubricating oil from the air flow meshings.

[0064] The meshing device 300, 300' according to [fig.6] comprises at least: - an input pinion adapted to cooperate with a transmission shaft, - an output pinion forming a gear with the input pinion and possibly a first deflector shrouding at least part of the input pinion.

[0065] With reference to [fig.6], when the meshing device 300 is positioned at the input gearbox (IGB) 220, said device 300 comprises: - an input pinion 212 with a straight blade connected to the transmission shaft 211 of [fig.5], - an output pinion 216 with a conical blade, connected to the transmission shaft 215 of [fig.l], - a first deflector 301, - a second deflector 302, - a 303 crankcase, - bearings or bearings 305, 306 for holding the pinions in the casing and nozzles 30, 30' bringing the lubricant to the internal walls of the pinions.

[0066] Furthermore, in a second embodiment also shown in [fig.6], the meshing device 300' is positioned at the level of the transfer gearbox TGB 221. In this second embodiment, the meshing device comprises: - an input pinion 217 with a straight blade connected to the transmission shaft 215 of [fig.l], - an output pinion 218 with a conical blade connected to the output shaft 219 of [fig.l], - the first deflector 301, - the second deflector 302, - the 303 casing, - bearings or bearings 307, 308 for holding the pinions in the casing and the nozzles 30, 30' bringing the lubricant to the internal walls of the pinions.

[0067] It is noted according to the example shown that the pinions 216, 218 are provided with the grooves 15a of the first embodiment of the lubrication device of the invention while the pinions 212, 217 are provided with the tubular channels 15b of the second embodiment of the lubrication device of the invention. However, it is possible to equip only one of the two pinions with a lubrication device of the invention if the lubrication requirements do not require a very high supply of lubricant.

[0068] The input and output pinions here form angle gears.

[0069] The invention, which applies to any type of pinion gearing, in particular high-speed gearing of turbomachines such as aeronautical turbomachines, is not limited to the examples described above, only by way of example, and, as seen previously, the pinions with a conical or straight blade may be straight pinions or provided with straight teeth.

Claims

Claims

1. Pinion (10a, 10b) extending around an axis of a shaft (11), comprising teeth (13) carried by a crown (14) connected to said shaft by a conical web (12) which extends from an end of the shaft and widens towards the crown (14) away from said end, characterized in that it comprises a lubrication device comprising a lubricant inlet on an internal wall of the conical web (12) and channels (15a, 15b), hollowed out in the crown (14) which open into hollows (13a) between the teeth (13) of the pinion.

2. Pinion (10a, 10b) according to claim 1, wherein said channels (15a, 15b) open at the level of the hollows between the teeth on the side of the axis (A) of rotation of the pinion.

3. Pinion according to claim 1 or 2, for which the channels are grooves (15a) hollowed out in an internal wall (141) of the crown on the rotation axis side, said grooves opening into the hollows of the teeth at the end of the teeth on the rotation axis (A) side.

4. Pinion according to claim 1 or 2, for which the channels are tubular channels (15b) opening on a first side through lubricant inlet holes (152) in the web or in an internal wall (141b) of the crown extending the web and on a second side through lubricant outlet holes (151) at the bottom of the hollows (13a) between the teeth (13) to bring the lubricant into these hollows.

5. Pinion (10a, 10b) according to any one of the preceding claims, for which the internal wall (141a, 141b) of the crown (14) comprises an internal rim (14a, 14b) curved at a junction between the internal wall of the conical web and the crown so as to produce an annular hollow forming a reserve for the lubricant pressed against said internal wall (141a, 141b) by the centrifugal force caused by the rotation of the pinion.

6. A sprocket according to any preceding claim, wherein the number of channels is equal to the number of hollows between the teeth.

7. A sprocket according to any preceding claim, wherein the sprocket is a straight or bevel gear.

8. A pinion according to any preceding claim, wherein the pinion is a helical or straight toothed pinion.

9. A lubricated meshing device comprising at least one first pinion (10a, 10b) according to any one of the preceding claims. preceding, at least one nozzle (30) whose outlet is directed towards the web of said first pinion and a second pinion (20) provided or not with a lubrication device, the first pinion being meshed with the second pinion.

10. A lubricated gear device according to claim 9 wherein the nozzle (30) deposits the lubricant on the shaft-side web (12) so that the centrifugal force caused by the rotation of the pinion spreads the lubricant on the web towards the channels (15a, 15b).

11. Gearbox (220, 221) of a turbomachine comprising a meshing device according to claim 9 or 10.

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